WO2018155432A1

WO2018155432A1 - Mesoporous catalyst body and gas treatment apparatus using same

Info

Publication number: WO2018155432A1
Application number: PCT/JP2018/005984
Authority: WO
Inventors: 貴紀松本; 中山　鶴雄; 洋平直原; 真雨宮; 真吾秋田; 悠輔山内
Original assignee: 株式会社Ｎｂｃメッシュテック; 国立研究開発法人物質・材料研究機構
Priority date: 2017-02-23
Filing date: 2018-02-20
Publication date: 2018-08-30
Also published as: TWI746806B; TW201842967A; JPWO2018155432A1; JP7082376B2

Abstract

[Problem] To provide a catalyst body which is capable of maintaining the activity for a long period of time. [Solution] A mesoporous catalyst body which is provided with: a supporting body that has a plurality of mesopores; and oxidation catalyst particles that are supported within the mesopores of the supporting body and contain at least one substance selected from among noble metals, oxides of noble metals, and alloys of a noble metal and a transition metal. The supporting body is configured such that one mesopore is in communication with at least one other mesopore.

Description

Mesoporous catalyst body and gas processing apparatus using the same

The present invention relates to a catalyst body capable of decomposing organic components such as ethylene, carbon monoxide, ammonia and the like in gas.

Since exhaust gas generated from internal combustion engines such as automobiles and factories contains trace amounts of harmful components such as carbon monoxide, they are released into the atmosphere after they are removed using removal means. In addition, in a closed storage room or the like, a trace amount of malodorous substances may be produced and ammonia odor may be generated, and various removal means are applied.
In addition, it is known that a variety of trace amounts of organic gas are released from plants, but ethylene gas having a ripening action is also released from agricultural crops during storage, and the ripening of the plant is progressing. Therefore, keeping the temperature and humidity constant and reducing the ethylene gas concentration are said to be effective for maintaining the freshness for a long time.

As a method for removing components contained in the gas, adsorption to an adsorbent such as activated carbon, radicals by a plasma generator, and decomposition and removal methods by active species such as ozone are widely used. However, in the adsorption treatment with an adsorbent, there is an upper limit on the amount of adsorbent adsorbed, and periodic adsorbent replacement is necessary. The treatment method using active species such as plasma requires a generator of a certain size, is not a method that requires electric power to operate and can be used simply, and in the storage of agricultural products, it seems that decolorization etc. Cannot be used due to concerns over the above changes.
In addition to the method of oxidative decomposition using physically generated active species such as the plasma method described above, a method of oxidative decomposition of components contained in gas using a catalyst is also widely used. As the oxidation catalyst body, in order to widen the contact area, a structure in which an active substance (catalyst particles) is supported on a carrier that is inorganic particles is used (Patent Document 1), or a membrane in which the active substance is made porous is used. A method for treating a volatile organic compound is disclosed (Patent Document 4). In addition, a catalyst body in which catalyst particles are supported in the pores of an inorganic mesoporous carrier having cylindrical mesopores has been developed, and a catalyst body or active material in which catalyst particles are supported on the outer surface of the inorganic particles has been developed. Compared with a porous membrane, a catalyst body having a very wide specific surface area and high activity has been obtained (Patent Documents 2 and 3).

Japanese Patent Laid-Open No. 2003-080077 JP 2004-283770 A JP 2007-326094 A JP 2006-326530 A

However, the catalyst body in which the oxidation catalyst particles are supported on the above-described cylindrical mesoporous carrier has a problem that the catalytic activity decreases with use. The cause is not clearly understood, but the components to be treated by blocking the contact between the catalyst particles and the gas to be treated by the adsorption of moisture in the atmosphere and water generated by oxidation reaction into the pores. It is conceivable that the decomposition reaction does not proceed, or the pores are sealed with adsorbed water, and the flow of the gas to be treated into the pores itself is hindered.
An object of this invention is to provide the catalyst body which can maintain activity for a long period of time, and the gas processing apparatus using the same.

The gist of the present invention is as follows.
[1] a support having a plurality of mesopores;
Oxidation catalyst particles comprising at least one of a noble metal, an oxide thereof, and an alloy of the noble metal and a transition metal supported in mesopores of the support,
A mesoporous catalyst body, wherein one mesopore communicates with at least one other mesopore in the support.
[2] Support having mesopores obtained by drying and baking a solution containing a hydrolyzate of alkoxysilane or metal alkoxide and polyoxyethylene alkyl ether, polyalkylene oxide triblock copolymer or cationic surfactant And a mesopore of the support by subjecting the body to a solution or colloidal solution of a compound corresponding to at least one of the noble metal, its oxide, and an alloy of the noble metal and the transition metal, followed by firing and / or reduction treatment. A mesoporous catalyst obtained by forming oxidation catalyst particles containing at least one of the noble metal, its oxide, and an alloy of the noble metal and transition metal.
[3] The mesoporous catalyst body according to [1] or [2], wherein the support is formed of a metal oxide or SiO ₂ .
[4] The catalyst body according to [3], wherein the metal oxide is a compound selected from the group consisting of TiO ₂ , Fe ₂ O ₃ , ZrO ₂ , and CeO ₂ .
[5] The mesoporous catalyst body according to any one of [1] to [4], wherein the noble metal is one or more selected from the group consisting of gold, platinum, and palladium.
[6] The mesoporous catalyst body according to any one of [1] to [5], wherein the support is a powder.
[7] The mesoporous catalyst body according to any one of [1] to [6], wherein an average pore diameter of the mesopores measured by BET method is 2 nm or more and 10 nm or less.
[8] The mesoporous catalyst body according to any one of [1] to [7], wherein an average particle diameter of the oxidation catalyst particles is 1 nm or more and 10 nm or less.
[9] The mesoporous catalyst according to any one of [1] to [8], wherein the supported amount of the oxidation catalyst particles is 0.1 to 30% by mass with respect to the support including the oxidation catalyst particles. .
[10] The mesoporous catalyst body according to any one of [1] to [8], wherein the mesoporous catalyst body is a gas oxidation reaction catalyst.
[11] At least a first electrode, a second electrode, and a dielectric disposed between the first electrode and the second electrode, the first electrode and the second electrode A plasma generating section for generating plasma by applying a voltage between and generating a discharge;
A flow path formed in a region where the plasma generated by the plasma generation unit is present and in which a gas to be processed flows;
A gas processing apparatus comprising: the mesoporous catalyst body according to any one of [1] to [10] disposed in the flow path.
[12] A support having mesopores obtained by drying and calcining a solution containing an alkoxysilane or metal alkoxide hydrolyzate and a polyoxyethylene alkyl ether, a polyalkylene oxide triblock copolymer or a cationic surfactant Is contacted with a solution or colloidal solution of a compound corresponding to at least one of the noble metal, its oxide, and an alloy of the noble metal and the transition metal, and is subjected to firing and / or reduction treatment in the mesopores of the support. And forming an oxidation catalyst particle containing at least one of the noble metal, its oxide, and an alloy of the noble metal and the transition metal.

According to the present invention, it is possible to provide a catalyst body capable of maintaining the activity for a longer period of time and a gas treatment apparatus using the catalyst body.

It is the figure which represented typically a part of cross section of the gas treatment apparatus 200 of 1st Embodiment. It is the figure which represented typically a part of cross section of the gas treatment apparatus 300 of 2nd Embodiment. It is the figure which represented typically a part of cross section of the gas treatment apparatus 400 of 3rd Embodiment. It is the figure which represented typically a part of cross section of the gas treatment apparatus 500 of 4th Embodiment. It is a three-dimensional tomography image which can understand that the catalyst body of Example 1 has a communication structure. It is a three-dimensional tomography image which can understand that the catalyst body of Example 1 has a communication structure. It is a three-dimensional tomography image which can understand that the catalyst body of Example 1 has a communication structure.

Hereinafter, embodiments of the present invention will be described in detail.
The mesoporous catalyst body of the present embodiment (hereinafter also simply referred to as catalyst body) is a member having air permeability, and has a plurality of mesopore diameter pores (mesopores) that are open on the surface of the support and allow gas to pass therethrough. And an oxidation catalyst particle (hereinafter referred to as an oxidation catalyst particle) comprising at least one of a noble metal, a noble metal oxide and an alloy of a noble metal and a transition metal supported in mesopores of the support. In some cases). In the catalyst body of this embodiment, one mesopore included in the support is in communication with at least one other mesopore.

The catalyst body of this embodiment can decompose components to be treated such as organic gas into carbon dioxide, water, etc. by an oxidation reaction and discharge them to the atmosphere. Gases that can be treated in the catalyst body of the present embodiment are not particularly limited, but carbon monoxide in tobacco sidestream smoke, compounds emitted from plants such as agricultural products and flower buds, automobile interior materials, residential building materials, Examples include materials that volatilize from materials such as interior materials and casings and members of home appliances, and substances that volatilize from organic solvents such as paints, adhesives, and cleaning agents. Specifically, hydrocarbons such as methane, ethane, propane, butane, ethylene, propylene, isoprene, benzene, xylene, toluene, ethylbenzene, styrene, α-farnesene, β-farnesene, methanol, ethanol, propane-1- All, butan-1-ol, pentan-1-ol, hexane-1-ol, heptane-1-ol, octan-1-ol, trans-2-hexenol, cis-2-hexenol, trans-3-hexenol, Alcohols such as cis-3-hexenol, linalool, benzyl alcohol, formaldehyde, acetaldehyde, propionaldehyde, butanal, pentanal, nonanal, benzaldehyde, hexanal, trans-2-hexenal, cis-2-hexa Aldehydes such as nal, trans-2-octenal, trans-2-nonenal, cis-2-nonenal, trans, cis-2,6-nonadienal, trans, cis-2,4-decadienal, acetone, ethylmethyl Ketones such as ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone, methyl formate, ethyl acetate, pentyl acetate, isopentyl acetate, octyl acetate, hexyl acetate, benzyl acetate, methyl butyrate, ethyl butyrate, pentyl butyrate, methyl salicylate, Ethyl caproate, pentyl valerate, ethyl-2-methylpropanoate, ethylbutanoate, methyl-2-methylbutanoate, ethyl-2-methylbutanoate, ethyl-3-methylbutanoate, methyl- 3-hydroxybutano , Methylhexanoate, ethylhexanoate, hexylhexanoate, methyl-3-hydroxyhexanoate, octylhexanoate, ethyloctanoate, methyl-3-hydroxyoctanoate, ethyl nicotinate, Esters such as γ-hexalactone, γ-octalactone, δ-octalactone, γ-decalactone, δ-decalactone, γ-dodecalactone, δ-dodecalactone, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, capron Carboxylic acids such as acid, enanthic acid, caprylic acid, 2-methylpropanoic acid and 2-methylbutanoic acid, terpenes such as trans-nerolidol, cis-nerolidol and farnesol, phenols such as eugenol and vanillin, ammonia and trimethylamine , Triethylamine, etc. And thiols such as methanethiol, ethanethiol, and propanethiol, and sulfur organic compounds such as methyl sulfide, methyl disulfide, and dimethyl sulfoxide.
Among these, decomposition of ethylene, oxygen monoxide, and the like is preferable because catalytic activity is maintained for a longer time when the catalyst body of the present embodiment is used. Further, when ethylene is to be decomposed, a support is formed from SiO ₂ , and the oxidation catalyst particles are made of platinum, platinum oxide, an alloy of platinum and a transition metal, palladium, palladium oxide, and an alloy of palladium and a transition metal. It is more preferable to include one or more selected from the group consisting of platinum, platinum oxide, and one or more selected from the group consisting of platinum and transition metal alloys. More preferably, platinum oxide is even more preferable. More preferably, when carbon monoxide is to be decomposed, a support is formed from a metal oxide, and the oxidation catalyst particles include gold and / or an alloy of gold and a transition metal.

In this specification, the mesopore is a pore having a diameter of 2 nm or more and 50 μm or less obtained by the BET method, and an opening on the surface of the catalyst body is a pore communicating with another opening. The shape of the mesopores and the positional relationship between the openings are not particularly limited.

In the catalyst body of the present embodiment, one mesopore is branched inside the support and communicates with another mesopore (hereinafter also referred to as a communication structure). Whether or not the support has a communication structure can be confirmed by a three-dimensional transmission electron microscope (TEM).

The catalyst body of the present embodiment can be in various forms such as powder, particle body, and film. Among these, it is preferable to have a film-like form, particularly a film-like form having a film thickness of 1000 nm or less, since the catalyst efficiency is hardly lowered. Further, powder is preferable because it can be used in various shapes. In the case of powder, the size is not particularly limited, and can be appropriately set by those skilled in the art.

By exposing the gas to be treated to the catalyst body of this embodiment, the gas to be treated diffuses into the catalyst body and comes into contact with the oxidation catalyst particles in the pores, and the components to be treated such as organic gas are oxidatively decomposed. Is done.
The conventional powdery mesoporous catalyst body has a cylinder structure in which the mesopores do not have a communication structure, and the opening on the upper surface of the support and the opening on the lower surface of one mesopore communicate in a straight line. It was. In this case, the air permeability of this mesopore is lost if there is even one blockage portion due to adsorbed water in the mesopore, but there is a part where the distance to the airflow is relatively long inside the mesopore, especially in the case of powder. In this part, the desorption of moisture adsorbed inside the powder is difficult to occur. Therefore, in the conventional mesoporous catalyst body, it is presumed that the mesopores are easily blocked by the adsorbed water, and the catalytic activity is lowered.
On the other hand, in the communication structure, the mesopores are connected to each other inside the support, so that even if moisture adheres to the inside of the support, the air permeability is hardly impaired, and the oxidation catalyst particles carried in the support mesopores and the gas to be treated It is difficult to prevent contact with As a result, the catalytic activity can be maintained for a longer period regardless of the shape of the catalyst body, such as powder, granules, and films.

In addition, in the catalyst body of this embodiment, as long as it has a communication structure and can achieve the object of the present invention, a part of the mesopores that does not communicate with other mesopores may be included.

In the catalyst body of the present embodiment, the diameter of the mesopores is not particularly limited as long as the above definition is satisfied, but the average diameter by the BET method is 2 nm or more and 10 nm or less, and the particle diameter of the supported oxidation catalyst particles is also This is preferable because it is within the above range and a highly active catalyst body can be obtained.
Note that the diameter of the pores of the support according to the present embodiment is a value calculated using an automatic specific surface area / pore distribution measuring device based on the BET method based on JIS-Z-8831.

The oxidation catalyst particles are not particularly limited as long as they are particles containing at least one of a noble metal having a catalytic function for promoting an oxidation reaction, a noble metal oxide, and an alloy of a noble metal and a transition metal.
As used herein, noble metals refer to gold, silver and platinum group ruthenium, rhodium, palladium, osmium, iridium and platinum. The noble metal oxide is an oxide of the above-mentioned noble metal or a hydrate thereof, specifically, Au ₂ O ₃ , Ag ₂ O, AgO, Ag ₂ O · Ag ₂ O ₃ , RuO ₂ , RuO ₄ , Rh ₂ O ₃ , PdO, OsO ₂ , OsO ₄ , IrO ₂ , Ir ₂ O ₃ .nH ₂ O, PtO ₂ , PtO ₂ .H ₂ O, platinum black and the like can be mentioned.
The transition metal of the alloy is not particularly limited as long as it can form an alloy with a noble metal, but Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, W etc. are mentioned.
Preferably, one or more selected from the group consisting of gold, platinum, palladium, their oxides, and an alloy of at least one of gold, platinum and palladium and a transition metal having higher oxidation catalytic ability The oxidation catalyst particles may be configured to include In this case, one or two selected from the group consisting of Au, Pt, Pd, PdO, Au ₂ O ₃ , PtO ₂ , PtO ₂ .H ₂ O, and platinum black are used as the constituent components of suitable oxidation catalyst particles. The particle | grains comprised from a seed | species or more are mentioned.

If the average particle size of the oxidation catalyst particles is 10 nm or less (more preferably 1 nm or more and 10 nm or less, even more preferably 1 nm or more and less than 10 nm, even more preferably 1 nm or more and 6 nm or less), the specific surface area of the oxidation catalyst particles increases. The catalytic activity is greatly improved, and the decomposition efficiency of the component to be processed in the gas to be processed is further increased, which is preferable.
The average particle diameter of the oxidation catalyst particles can be obtained as an average value obtained by calculating the particle size in an image photograph of a transmission electron microscope (TEM).

The oxidation catalyst particles are preferably supported on the support containing the oxidation catalyst particles in an amount of 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, and 0.5 to 10% by mass. % Is even more preferred. When it is supported in an amount of more than 30% by mass, the oxidation catalyst particles are easily aggregated, and the catalytic activity is reduced as compared with the case of being within the range. If it is less than 0.1% by mass, it is not preferable because sufficient catalytic activity cannot be obtained as compared with the case of being in the range.

In addition, in addition to the oxidation catalyst particles, the catalyst body of the present embodiment may include promoter particles and various metal elements, and is not particularly limited. Specifically, the catalyst may be a mixture of cocatalyst particles and oxidation catalyst particles, or a composite catalyst composed of composite particles obtained by combining various metal elements with oxidation catalyst particles. When the oxidation catalyst particles are used alone or when a promoter is mixed with the oxidation catalyst particles, the oxidation catalyst particles may be within the above-mentioned size range. In the case of composite particles in which other metal elements are combined, the size of the composite particles may be within the above-mentioned size range. Examples of metal particles (nanoparticles) other than the catalyst particles used in the promoter or composite catalyst include base metals and oxides thereof. Two or more kinds of these noble metal and oxide thereof, base metal and oxide thereof may be mixed and supported on the inner surface of the support pore.

In consideration of the fact that the support having mesopores according to the present embodiment may be produced including a step of forming mesopores using a compound as a template and removing the compound by heating, the heating temperature or higher is considered. It is preferable to be made of a material that does not deteriorate.

The support according to the present embodiment can be formed from a metal oxide. The support composed of the metal oxide can act on the catalyst particles and enhance the catalytic activity of the catalyst body.
The metal oxide is a metal oxide, and the metal is a group 1 (excluding H), a group 2 to 12, a group 13 (excluding B), or a group 14 (excluding C and Si) in the periodic table. , Elements belonging to Group 15 (excluding N, P and As) and Group 16 (excluding O, S, Se, and Te), and lanthanoids and actinoids. Examples of the metal oxide include γ-Al ₂ O ₃ , α-Al ₂ O ₃ , θ-Al ₂ O ₃ , η-Al ₂ O ₃ , amorphous Al ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO. _{_{_{_{2, MgO, ZnO 2, Bi}}}} 2 O 3, In 2 O 3, MnO 2, Mn 2 O 3, Nb 2 O 5, FeO, Fe 2 O 3, Fe 3 O 4, Sb 2 O 3, CuO, Cu ₂ O, NiO, Ni ₃ O ₄ , Ni ₂ O ₃ , CoO, Co ₃ O ₄ , Co ₂ O ₃ , WO ₃ , CeO ₂ , Pr ₆ O ₁₁ , Y ₂ O ₃ , In ₂ O ₃ , PbO, metal oxides such as ThO ₂ and the like. Also, metal oxides, _{_{_{_{e.g., Al 2 O 3 -TiO 2,}}}} Al 2 O 3 -ZrO 2, Al 2 O 3 -CaO, Al 2 O 3 -CeO 2, Al 2 O 3 -Fe 2 O 3, _{_{_{TiO 2 -CeO 2, TiO2-ZrO}}} 2, TiO 2 -WO 3, ZrO 2 -WO 3, SnO 2 -WO 3, CeO 2 -ZrO 2, Al 2 O 3 -TiO 2 -ZrO 2, cerium-zirconium It may be a composite oxide containing two or more metals such as bismuth composite oxide. Note that the cerium-zirconium-bismuth composite oxide is a solid solution represented by the general formula _{_{Ce 1-X-Y Zr X}} Bi Y O 2-δ, X, Y, the value is 0.1 ≦ X ≦ each [delta] 0 .3, 0.1 ≦ Y ≦ 0.3, 0.05 ≦ δ ≦ 0.15.
Further, the support may be formed of SiO _2.

The material of these supports may be selected according to the type of gas to be treated, the equipment to which the catalyst is applied, and various environmental conditions. SiO ₂ , TiO ₂ , Fe ₂ O ₃ , ZrO ₂ , and CeO ₂ are more desirable because they can support the catalyst particles more firmly and can adhere more firmly to the substrate when the substrate is used.

As above-mentioned, the shape of the support body which the catalyst body of this embodiment has is not specifically limited, For example, it can be set as a powder, a granular form, a film | membrane form, etc. On the other hand, the shape of the support is preferably a film.
When the support is in the form of a film, the distance from the mesopores where the oxidation catalyst particles are present to the gas flow of the gas to be treated is shorter than that of other shapes such as powder. Therefore, when moisture in the gas is adsorbed in the mesopores of the membrane-like catalyst body, a concentration gradient to the gas flow to be treated occurs, and the re-diffusion of the adsorbed water into the air flow proceeds. It is suppressed to a certain amount. Accordingly, when the support has a film-like shape, the mesopores are less likely to be blocked.
In the present specification, the film-like shape means a shape such as a layer that separates a space or covers at least a part of an object.

The catalyst body of the present embodiment can be formed in a film shape on a substrate, for example. At this time, whether or not the base material has air permeability is not particularly limited. When the catalyst body of the present embodiment is disposed on a non-breathable substrate, irregularities may be formed on the surface of the catalyst body by embossing or the like. When irregularities are formed on the surface of the catalyst body, the contact area with the flowing gas increases, and the oxidation reaction of the gas to be treated can be further promoted.

If the catalyst body of this embodiment is a base material that is formed into a film on its surface, such as a filter or mesh, the gas to be treated is circulated in the thickness direction of the catalyst body of this embodiment. It doesn't matter. In addition, when the substrate has a shape such as a plate shape, the catalyst body of the present embodiment may be formed on both surfaces of the substrate, and in which form the catalyst body of the present embodiment is incorporated. What is necessary is just to decide according to the design etc.

When the catalyst body of the present embodiment has a film shape, the film thickness is desirably 50 nm or more and 1000 nm or less. If it is less than 50 nm, the absolute amount of the catalyst is reduced, so that it is difficult to decompose the organic gas in the gas to be treated as compared with the case where it is within the range. If it is larger than 1000 nm, the moisture adsorbed in the mesopores existing at a position away from the gas to be treated is difficult to be re-released, the amount of moisture adsorbed in the pores increases, and the action of the oxidation catalyst particles is inhibited. Compared with the case where it exists in the range, the catalyst efficiency of the said catalyst body falls.
The film thickness when the catalyst body of the present embodiment has a film shape can be measured by observing the cross section of the film with a TEM and measuring the size of the cross-sectional image.

The catalyst body of the present embodiment can be formed on a substrate. In the case where the catalyst body of the present embodiment is formed in a film form on the substrate, it is preferable because the thickness of the catalyst body can be more easily reduced. As described above, the base material may be a non-breathable structure such as a plate shape or a breathable structure. Examples of the air-permeable structure include a sheet-like structure in which a large number of through-holes are formed by punching, a fiber-like, cloth-like, or mesh-like fiber made of a woven fabric, a net, a nonwoven fabric, or the like. A structure (filter shape) can be mentioned. In addition, various shapes and sizes suitable for the purpose of use can be used as appropriate.

Since the base material on which the film-like catalyst body is formed may be heated when the support is formed in a film form, it is desirable to use a material having heat resistance that can withstand the heating temperature. Specifically, metal materials, ceramics, glass, carbon fibers, silicon carbide fibers, heat resistant organic polymer materials, and the like are preferable, and metals, metal oxides, and glass are more preferable.

Metal materials used for the substrate include high melting point metals such as tungsten, molybdenum, tantalum, niobium, TZM (Titanium Zirconium Molybdenum), W-Re (Tungsten-rhenium), noble metals such as silver and ruthenium, and alloys thereof. Or oxides, special metals such as titanium, nickel, zirconium, chromium, inconel, hastelloy, general metals such as aluminum, copper, stainless steel, zinc, magnesium, iron and alloys containing these general metals or oxides of these general metals Can be used. In addition, a member on which the above-described metal, alloy, or oxide film is formed by various plating and vacuum deposition, a CVD method, a sputtering method, or the like may be used as a metal material.

Note that a natural oxide thin film is usually formed on the metal surface and the alloy surface thereof, and when the support is formed from a silane compound, the base oxide and the support are strengthened using the natural oxide thin film. Can be fixed. In this case, it is preferable to remove oil and dirt adhering to the surface of the oxide thin film in advance by an ordinary known method in order to fix stably and firmly. Also, instead of using a natural oxide film, an oxide thin film is chemically formed on a metal surface or alloy surface by a known method, or an oxide thin film is formed by a known electrochemical method such as anodic oxidation. Also good.

Furthermore, examples of ceramics used for the base material include ceramics such as earthenware, ceramics, stoneware and porcelain, and ceramics such as glass, cement, gypsum, enamel and fine ceramics. The composition of the ceramics to be composed can include elemental, oxide-based, hydroxide-based, carbide-based, carbonate-based, nitride-based, halide-based, phosphate-based, etc. It may be a composite.

In addition, as ceramics used for the base material, barium titanate, lead zirconate titanate, ferrite, alumina, forsterite, zirconia, zircon, mullite, steatite, cordierite, aluminum nitride, silicon nitride, carbonized Examples thereof include silicon, new carbon, and new glass, and ceramics such as high-strength ceramics, functional ceramics, superconducting ceramics, nonlinear optical ceramics, antibacterial ceramics, biodegradable ceramics, and bioceramics.

The glass used for the substrate is soda lime glass, potash glass, crystal glass, quartz glass, chalcogen glass, uranium glass, water glass, polarizing glass, tempered glass, laminated glass, heat resistant glass / borosilicate glass, bulletproof glass. , Glass fiber, dichroic glass, gold stone (brown gold stone / sand gold stone / purple gold stone), glass ceramics, low melting point glass, metallic glass, and glass such as saphiret.

Other base materials include ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, medium heat Portland cement, low heat Portland cement, sulfate-resistant Portland cement, and Portland cement with blast furnace slag, fly ash and silica. It is also possible to use cements such as blast furnace cement, silica cement, and fly ash cement, which are mixed cements to which a quality mixed material is added.

In addition, titania, zirconia, alumina, ceria (cerium oxide), zeolite, apatite, silica, activated carbon, diatomaceous earth, and the like can be used as the base material. Furthermore, metal oxides such as chromium, manganese, iron, cobalt, nickel, copper, and tin can be used for the substrate.
In addition, polyimide, polyether ether ketone, polyphenylene sulfide, polyaramide, polybenzothiazole, polybenzoxazole, polybenzimidazole, polyquinoline, polyquinoxaline, fluororesin, etc., thermosetting such as phenol resin and epoxy resin It is also possible to use a heat-resistant organic polymer material known to those skilled in the art, such as an adhesive resin.

Next, an example of a method for obtaining the catalyst body of the present embodiment will be described.
The catalyst body of the present embodiment includes, for example, a support having mesopores obtained by drying and calcining a solution containing an alkoxysilane or metal alkoxide hydrolyzate and a surfactant, a noble metal, its oxide, Alternatively, a solution of a compound corresponding to at least one of an alloy of a noble metal and a transition metal or a colloidal solution of the noble metal compound is brought into contact, and subjected to firing and / or reduction treatment, and the noble metal and its oxide in the mesopores of the support Alternatively, it can be obtained by forming oxidation catalyst particles containing at least one of an alloy of a noble metal and a transition metal.

In the method, first, a support is formed.
For a support having mesopores, for example, a precursor of a support containing a substance that acts as a template for mesopores is formed inside, and then a substance that acts as a template is decomposed and removed to form mesopores. Can be obtained.
An example of the method will be described. First, a solution containing a surfactant as a template and a hydrolyzate of alkoxysilane or metal alkoxide (hereinafter referred to as a precursor solution) is prepared. Specifically, for example, an alkoxysilane or metal alkoxide is added to a solution in which a surfactant is dissolved, and the pH is adjusted to hydrolyze the alkoxysilane or metal alkoxide. As a result, a hydrolyzate having a silanol group or a metal hydroxide is produced. The surfactant forms micelles in the solution and becomes a template for mesopores. The precursor solution is heated to volatilize the solvent, and the silanol group or metal hydroxide is condensed and cured to form a precursor of the support. Thereafter, the substrate is further baked to a high temperature of 300 ° C. or more to remove the surfactant as a template in the precursor by decomposing and volatilizing, thereby obtaining a support having mesopores.
The film-like support can be obtained, for example, by heating the precursor solution after being applied to the substrate to volatilize the solvent and perform condensation curing. Further, if the precursor solution is made into particles with a spray dryer or the like and then solvent evaporation and condensation curing are performed, a powdery support can be obtained. The powder support may be obtained by pulverizing after obtaining a solid support in the above-described step.

For example, the precursor solution can include three components: (1) a hydrolyzate of alkoxysilane or metal alkoxide, (2) a solvent (solvent), and (3) a surfactant. When hydrolyzing an alkoxysilane or metal alkoxide in a solution to obtain a hydrolyzate, water is required, so the solvent should be water or a mixed solvent of water and alcohols such as ethanol or methanol. Is preferred. Further, a catalyst for hydrolysis treatment of alkoxysilane or metal alkoxide may be further included in the solution, and it is preferable to use an acid such as nitric acid or hydrochloric acid as the catalyst.
The ratio of the surfactant, the alkoxysilane, or the metal alkoxide is not particularly limited, can be set as appropriate, and is not particularly limited. By changing the molar ratio of surfactant / alkoxysilane or metal alkoxide, the pore volume ratio and the porosity of the obtained support can be controlled.

In addition, when forming a film-like support, it is preferable from the viewpoint of forming a film having a more uniform film thickness so that precipitates are not generated in the precursor solution before application to the substrate, and the pH is Precipitation of the precursor can be avoided by using an acidic alcohol. Alternatively, the precipitation can be achieved by adjusting only the molar ratio of water to alkoxysilane or metal alkoxide, adjusting the molar ratio with pH adjustment, or adding alcohol, or both molar ratio adjustment and alcohol addition. It can also be avoided.

As the surfactant, for example, a nonionic surfactant or a cationic surfactant can be used.
As the nonionic surfactant, for example, polyhydric alcohol fatty acid ester, polyoxyalkylene fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyalkylene oxide block copolymer and the like can be used.
Of these, it is desirable to use polyoxyethylene ether or polyalkylene oxide block copolymer as the nonionic surfactant because a catalyst in which the catalytic activity is less likely to decrease is obtained. For the same reason, it is also preferable to use a cationic surfactant.
Specific examples of the polyoxyethylene alkyl ether include C ₁₂ H ₂₅ (OCH ₂ CH ₂ ) _n OH (n is 2 to 100), C ₁₆ H ₃₃ (OCH ₂ CH ₂ ) _n OH (n is 2 to 100). , C ₁₈ H ₃₇ (OCH ₂ CH ₂ ) _n OH (n is 2 to 100), etc., can be used alone or in a mixture. Commercially available polyoxyethylene ethers such as Brij (registered trademark) 56, Brij76, Brij78 can also be used.
Examples of the polyalkylene oxide block copolymer include polyalkylene oxide triblock copolymers of ethylene oxide and propylene oxide, and more specifically, pluronic surfactants such as Pluronic (registered trademark) L121 and P123.
Examples of the cationic surfactant include distearyldimethylammonium chloride, benzalkonium chloride, cetylpyridinium chloride, hexadecyltrimethylammonium bromide, didecyldimethylammonium chloride, and decalinium chloride.

Since the molecular chain length of the surfactant affects the mesopore diameter, the surfactant may be selected according to the target mesopore diameter. Alternatively, a hydrophobic compound such as 1,3,5-trimethylbenzene, 1,3,5-triethylbenzene, 1,3,5-triisopropylbenzene, n-heptane may be added to the precursor solution. Since the hydrophobic compound can increase the micelle diameter in the precursor solution, it can be used to adjust the mesopore diameter.

Examples of the alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane. Hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, and the like.
Examples of the metal alkoxide include tetrapropoxyaluminum, tetrapropoxytin, tetrapropoxytitanium, and tetrapropoxyzirconium.

As described above, when a film-like support is formed on a substrate, the precursor solution is applied onto the substrate to form a film-like support. The method of applying the precursor solution to the substrate is not limited as long as the precursor solution can be uniformly and thinly applied, but there are a spin coating method and a Dip & blow method in which an unnecessary solution is blown off after the substrate is immersed in the precursor solution. Applicable and may be selected according to the shape of the substrate to be applied.
Also, the heating conditions for removing the template molecules after forming the precursor are not particularly limited, and the precursor may be heated at 300 to 600 ° C., for example.

Next, the oxidation catalyst particles are supported on the mesopores of the support to obtain the catalyst body of this embodiment. First, a solution or colloidal solution of a compound corresponding to at least one of a noble metal, its oxide, or an alloy of a noble metal and a transition metal contained in an oxidation catalyst particle to be supported on a support (hereinafter simply referred to as a noble metal compound solution). The noble metal compound solution is introduced into the mesopores of the support. When the alloy of the noble metal and the transition metal includes the oxidation catalyst particles, a solution obtained by further dissolving a transition metal salt in addition to the compound corresponding to the noble metal may be used as the noble metal compound solution. Then, the catalyst body of this embodiment can be obtained by performing oxidation and / or reduction treatment to form oxidation catalyst particles in the mesopores.
Specifically, for example, after immersing the support in a noble metal compound solution, firing and / or reduction treatment can be performed.
More specifically, the alkali solution is used to adjust the noble metal compound solution to 20 to 90 ° C., preferably 50 to 70 ° C. while stirring and stirring to a pH of 3 to 10, preferably 5 to 8. Next, the support is immersed in the noble metal compound solution, followed by vacuum degassing to allow the noble metal compound solution to penetrate into the pores. Thereafter, oxidation catalyst particles containing noble metal and the like in the pores can be obtained by heating and firing at 200 to 600 ° C.

In addition, as described above, after impregnating the noble metal compound solution into the pores, it is immersed in a sodium borohydride solution or a hydrogen reduction method in which a baking treatment at 200 to 600 ° C. and a exposure to a hydrogen stream at 100 to 300 ° C. are performed. The oxidation catalyst particles can also be formed in the pores by performing a known reduction operation such as a liquid phase reduction method. Depending on the type of compound contained in the noble metal compound solution, the oxidation catalyst particles can be obtained in the pores only by heating and baking at 200 to 600 ° C. without performing the above-described known reduction operation. Further, the reduction of the compound contained in the noble metal compound solution may be partially limited, and the noble metal alone and the noble metal oxide may coexist in the oxidation catalyst particles in the mesopores.

Corresponding to the noble metal constituting the oxidation catalyst particle, its oxide, or an alloy of noble metal and transition metal, as a compound containing a noble metal element, for example, as a gold compound, HAuCl ₄ · 4H ₂ O, NH ₄ AuCl ₄ , KAuCl ₄ · nH ₂ O, KAu (CN) ₄ , Na ₂ AuCl ₄ , KAuBr ₄ · 2H ₂ O, NaAuBr ₄ etc. for platinum compounds, chloroplatinic acid, dinitrodiammine platinum, dichlorotetraammine platinum etc. are palladium Examples of the compound include dinitrodiammine palladium and ammonium chloropalladate.
The concentration of the noble metal compound in the noble metal compound solution is not particularly limited, but it is preferable to prepare the solution at 1 × 10 ⁻² to 1 × 10 ⁻⁵ mol / L because the generated oxidation catalyst particles are unlikely to aggregate.
The transition metal salt that can be contained in the noble metal compound solution is not particularly limited as long as it is a compound that can be dissolved in the solution and does not cause precipitation even when it coexists with the metal compound corresponding to the above-mentioned noble metal or noble metal oxide. Illustrative are halides such as chlorides and bromides of transition metals, nitrates, carbonates, bicarbonates, carboxylates and the like. The concentration of the transition metal salt is not particularly limited, but it is preferable to prepare the solution at 1 × 10 ⁻² to 1 × 10 ⁻⁵ mol / L because the generated oxidation catalyst particles are unlikely to aggregate.

As described above, the catalyst body according to the present embodiment has an oxidation catalyst particle having at least one of a noble metal, a noble metal oxide, and an alloy of a noble metal and a transition metal in a mesopore in a support having a communication structure. By providing the structure to carry | support, activity can be maintained for a long term compared with the past.
Further, the catalyst body of this embodiment can decompose and remove ethylene and the like even at a temperature lower than room temperature (23.4 ° C.). Further, although depending on the size of the catalyst body, it can be decomposed and removed even at a concentration of about 0.5 ppm.
The mesoporous catalyst body of the present embodiment can be used to configure a member or device that can remove organic gas components and the like.
Such members and devices include filters such as air purifiers, air conditioners, refrigerators, air purification filters installed in warehouses and showcases, packaging members for fruits and flowers, exhaust gas purification devices such as internal combustion engines, Examples thereof include a steam reformer for a fuel cell. Furthermore, the mesoporous catalyst body of the present embodiment is provided in an article (freshness-preserving agent) used for sustaining a state that can withstand various uses such as raw food, food processing, and ornamental for fruits and vegetables. May be.

Next, a gas processing apparatus in which the catalyst body of this embodiment is used will be described. In the following description, a case where a film-like catalyst body (catalyst body film) is used as an example of the catalyst body of the present embodiment will be described.
FIG. 1 is a diagram schematically showing a part of a cross section of a gas processing apparatus 200 according to the first embodiment. The gas processing apparatus 200 according to the present embodiment includes a plasma and a catalyst body film 100 that generate a component to be processed in a gas to be processed supplied in the direction of arrow A to the gas processing apparatus 200 in the gas processing apparatus 200. It is a device that oxidizes and decomposes by function.

The gas processing apparatus 200 includes a plasma generation unit including an application electrode 11, a ground electrode 12, and a dielectric 13, and a (high voltage) power source 14 that is a power supply unit is connected to the application electrode 11. The ground electrode 12 and the application electrode 11 are disposed to face each other, and the dielectric 13 is disposed between the ground electrode 12 and the application electrode 11. The dielectric 13 is in close contact with only the ground electrode 12 and is separated from the application electrode 11. In the gas processing apparatus 200, the application electrode 11, the ground electrode 12, and the dielectric 13 are members / apparatus (plasma generation unit) for generating plasma, and are connected between the application electrode 11 and the ground electrode 12 by the power source 14. When a voltage is applied to the electrode, the application electrode 11, the ground electrode 12, and the dielectric 13 form a low-temperature plasma reaction layer (region where plasma exists) by discharge between the application electrode 11 and the dielectric 13. . One of the application electrode 11 and the ground electrode 12 is the first electrode, and the other is the second electrode. In another embodiment, when a plurality of application electrodes 11 and a plurality of ground electrodes 12 are combined, each of the plurality of electrodes of any one type is the first electrode and each of the plurality of electrodes of the other type is This is the second electrode. The dielectric 13 is provided only between the ground electrode 12 and the catalyst body film 100, but is not limited thereto. For example, in addition to the ground electrode 12 and the catalyst body film 100, the application electrode 11 is provided. And the catalyst body film 100 may be provided.

The application electrode 11 is an electrode to which a voltage is applied by the power source 14. The ground electrode 12 is grounded by a ground wire 12a. The application electrode 11, the ground electrode 12, and the dielectric 13 have a breathable structure through which the gas to be processed can pass. Specifically, examples of the structure of the application electrode 11, the ground electrode 12, and the dielectric 13 include a lattice shape, a saddle shape, a porous shape by punching, an expanded mesh shape, and a honeycomb shape. Two or more types of structures may be combined. The application electrode 11 and the ground electrode 12 may have a needle-like structure. The application electrode 11, the ground electrode 12, and the dielectric 13 may have the same shape / structure among the shapes / structures described above. In FIG. 1, the application electrode 11 has a large number of small openings as in a mesh, and the ground electrode 12 and the dielectric 13 have a large number of openings as in a porous shape by punching.

The gas to be processed supplied from the arrow A direction to the plasma generation unit reaches the low temperature plasma reaction layer formed between the application electrode 11 and the dielectric 13 through the opening formed in the application electrode 11. The gas to be processed that has reached the low-temperature plasma reaction layer is directly discharged to the outside of the plasma generation unit, or the outside of the plasma generation unit through the opening formed in the dielectric 13 and the opening formed in the ground electrode 12. To be discharged. In other words, the plasma generating portion includes an opening formed in the application electrode 11, the ground electrode 12, and the dielectric 13, and a flow composed of a low-temperature plasma reaction layer formed between the application electrode 11 and the dielectric 13. A road is formed.

Of the flow path formed in the plasma generation unit, a catalyst film 100 that is in close contact with the dielectric 13 and the application electrode 11 is disposed in the low-temperature plasma reaction layer (between the application electrode 11 and the dielectric 13). . For this reason, the to-be-processed gas which flowed through the flow path and reached the low-temperature plasma reaction layer can pass through the catalyst body film 100 via the mesopores. Therefore, the component to be processed in the gas to be processed is oxidized and decomposed by the function of the catalyst film 100 on which plasma acts.

As the application electrode 11 and the ground electrode 12 used in the gas processing apparatus 200, a material that functions as an electrode can be used. As a material of the application electrode 11 and the ground electrode 12, for example, a metal such as Cu, Ag, Au, Ni, Cr, Fe, Al, Ti, W, Ta, Mo, Co, or an alloy thereof can be used.

The dielectric 13 only needs to have a property of becoming an insulator. Examples of the material of the dielectric 13 include ZrO ₂ , γ-Al ₂ O ₃ , α-Al ₂ O ₃ , θ-Al ₂ O ₃ , η-Al ₂ O ₃ , amorphous Al ₂ O ₃ , and aluminate. Ride, mullite, stearite, forsterite, cordierite, magnesium titanate, barium titanate, SiC, Si ₃ N ₄ , Si-SiC, mica, glass and other inorganic materials, polyimide, liquid crystal polymer, PTFE (polytetrafluoro) ethylene), ETFE (ethylenetetrafluoroethylene), PVF (polyvinylfluoride), PVDF (polyvinylidene difluoride), polyetherimide, polyamideimide and the like. In view of plasma resistance and heat resistance, inorganic materials are more preferable.

As described above, when the catalyst body film 100 also has a function as a dielectric (for example, when a part of the catalyst body is an insulator), the catalyst body film 100 can also be used as a dielectric. The dielectric 13 may not be provided. Moreover, in the gas processing apparatus 200 of this embodiment, usage conditions, such as the quantity of the to-be-processed gas which flows into a flow path, and a flow rate, are not specifically limited. For example, a blower may be connected to the gas processing apparatus 200 and a predetermined amount of gas to be processed may be sent to the flow path at a predetermined flow rate. The gas processing apparatus 200 is left in the gas to be processed, and the gas to be processed naturally You may just flow into a flow path.

The power source 14 is a power source that can apply a high voltage. As the power source 14, a high voltage power source such as an alternating high voltage or a pulse high voltage, a power source in which an alternating current or a pulse is superimposed on a DC bias, or the like can be used. Examples of the AC high voltage include sine wave AC, rectangular AC, triangular AC, and sawtooth AC. A predetermined voltage may be applied between the application electrode 11 and the ground electrode 12 so that plasma is generated in the discharge space formed by the application electrode 11, the ground electrode 12, and the dielectric 13 by the power source 14. The voltage applied by the power source 14 varies depending on the concentration of the component to be processed contained in the gas to be processed, but can be usually 1 to 20 kV, preferably 2 to 10 kV. The type of discharge generated by the electric power supplied from the power supply 14 for generating plasma is not particularly limited as long as the plasma can be generated. For example, silent discharge, creeping discharge, corona discharge, pulse discharge, etc. I just need it. Further, two or more kinds of these discharges may be combined to generate plasma.

Also, the output frequency of the power source 14 is preferably a high frequency, specifically, 0.5 kHz or more. Furthermore, 0.5 kHz or more and 30 kHz or less are preferable, and 1 kHz or more and 20 kHz or less are more preferable. If the frequency is lower than 0.5 kHz, the amount of intermediate products and ozone produced may increase. If the frequency is higher than 30 kHz, decomposition due to oxidation may be suppressed for any component to be treated.

In this embodiment, the dielectric 13 is in close contact with the ground electrode 12, but the present invention is not limited to this. It is only necessary that plasma can be generated, and it is sufficient that the dielectric 13 is in close contact with at least one of the application electrode 11 and the ground electrode 12. Further, the dielectric 13 may be disposed in close contact with the application electrode 11 and the ground electrode 12, and the catalyst film 100 may be provided between the two dielectrics 13. Furthermore, when forming the catalyst body film 100 on the base material mentioned above, the dielectric 13 can also be utilized as a base material.

Next, the gas processing apparatus 300 of 2nd Embodiment is demonstrated. In the present embodiment, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, differences from the first embodiment will be mainly described.

FIG. 2 is a diagram schematically showing a part of a cross section of the gas processing apparatus 300 of the second embodiment. The gas processing apparatus 300 of this embodiment generates plasma by silent discharge. The gas processing apparatus 300 according to the present embodiment has a laminated structure in which two opposing dielectrics 13 are disposed between the application electrode 11 and the ground electrode 12, and each dielectric 13 is connected to the application electrode 11 and the ground. It is in close contact with the electrode 12.

The gas processing apparatus 300 forms a low-temperature plasma reaction layer by discharge between the two dielectrics 13 by applying a voltage between the application electrode 11 and the ground electrode 12 using the high voltage power supply 14. In FIG. 2, the dielectric 13 is laminated in close contact with both the application electrode 11 and the ground electrode 12, but only one of the dielectrics 13 may be provided.

In the gas processing apparatus 300 of the present embodiment, the application electrode 11, the ground electrode 12, and the dielectric 13 have a non-breathable structure through which the gas to be processed does not pass. Therefore, the gas to be processed that is supplied to the plasma generation unit from the direction of arrow a in FIG. 2 passes through the low-temperature plasma reaction layer formed between the two dielectrics 13 and is discharged to the outside of the plasma generation unit. (Direction of arrow b). That is, a flow path constituted by a low-temperature plasma reaction layer (a region where plasma exists) formed between the two dielectrics 13 is formed in the plasma generation unit. In the flow path formed in the low-temperature plasma reaction layer, two opposing catalyst body films 100 that are in close contact with different dielectrics 13 are arranged at a predetermined interval. For this reason, the to-be-processed gas which flows through a low-temperature plasma reaction layer can pass the catalyst body film | membrane 100 via a mesopore. Therefore, the component to be processed in the gas to be processed is oxidized and decomposed by the function of the catalyst body film 100 on which plasma acts, as in the first embodiment. Note that the catalyst body film 100 may or may not be in close contact with the dielectric 13. Although depending on the amount of gas to be processed, the catalyst film 100 should not be in close contact with the dielectric 13 when the pressure loss in the flow path becomes high. In this embodiment, the catalyst body film 100 may also be used as the dielectric 13, and the dielectric body 13 may be used as a base material on which the catalyst body film 100 is formed.

The gas processing device 300 has a multilayer structure, so that it is easy to secure a flow path. For this reason, it becomes easy to increase the amount of gas to be processed, and a large amount of components to be processed can be efficiently decomposed. The gas processing apparatus 300 is installed so that the component can be efficiently oxidized and decomposed according to the amount of the component to be processed and the use conditions such as the flow rate. The catalyst body film 100 may be either a single layer or a plurality of layers, and can be arbitrarily set.

Next, the gas processing apparatus 400 according to the third embodiment will be described. In the present embodiment, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, differences from the first embodiment will be mainly described.

FIG. 3 is a diagram schematically showing a part of a cross section of the gas processing apparatus 400 of the third embodiment. In the gas processing apparatus 400 of the present embodiment, two opposing ground electrodes 12, two dielectrics 13 disposed between the two ground electrodes 12, and an application disposed between the two dielectrics 13. An electrode 11 is provided. The ground electrode 12 and the dielectric 13 are in close contact with each other, and the dielectric 13 and the application electrode 11 are arranged at a predetermined interval. The gas processing apparatus 400 can generate plasma between the two dielectrics 13 and the application electrode 11 by applying a voltage between the application electrode 11 and the ground electrode 12 using the high voltage power supply 14. And two plasma reaction layers sandwiching the application electrode 11 can be formed.

In the gas processing apparatus 400 of the present embodiment, the ground electrode 12 and the dielectric 13 have a non-breathable structure through which the gas to be processed does not pass. On the other hand, the application electrode 11 has a plurality of openings and has a breathable structure through which the gas to be processed passes. For this reason, the gas to be processed supplied to the plasma generation unit from the direction of arrow a in FIG. 2 passes through the low temperature plasma reaction layer while moving through the two plasma reaction layers through the opening formed in the application electrode 11. Then, it is discharged outside the plasma generator. That is, an opening formed in the application electrode 11 and a flow path constituted by two plasma reaction layers are formed in the plasma generation unit.

Among the flow paths formed in the plasma generation unit, the catalyst film 100 that is in close contact with the application electrode 11 is disposed in each of the two low-temperature plasma reaction layers (between the two dielectrics 13 and the application electrode 11). Yes. For this reason, the to-be-processed gas which moves a flow path can pass the catalyst body film | membrane 100 via a mesopore. Therefore, the component to be processed in the gas to be processed is oxidized and decomposed by the function of the catalyst film 100 on which plasma acts.

As with the gas processing apparatus 300 of the second embodiment, the gas processing apparatus 400 has a multi-layer structure, which makes it easy to secure a flow path. For this reason, it becomes easy to increase the amount of gas to be processed, and a large amount of components to be processed can be efficiently decomposed. The gas processing apparatus 400 is installed so that the component can be efficiently oxidized and decomposed according to the amount of the component to be processed and the use conditions such as the flow rate. The catalyst body film 100 may be either a single layer or a plurality of layers, and can be arbitrarily set.

Next, a gas processing apparatus 500 according to the fourth embodiment will be described. In the present embodiment, members having the same functions as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, differences from the first embodiment will be mainly described.

FIG. 4 is a diagram schematically showing a part of a cross section of the gas processing apparatus 500 of the fourth embodiment. The gas processing apparatus 500 of this embodiment generates plasma by silent discharge and decomposes components to be processed. In the gas processing apparatus 500 of the present embodiment, the cylindrical application electrode 11, the catalyst body film 100, and the dielectric 13 are configured such that they are laminated radially outwardly in an annual ring shape with the columnar ground electrode 12 as the central axis. This is a cylindrical structure.

In the gas processing apparatus 500, two dielectrics 13 are provided. One dielectric 13 is disposed radially outside the ground electrode 12 and is in close contact with the ground electrode 12. The other dielectric 13 is disposed radially inside the application electrode 11 and is in close contact with the application electrode 11. The gas processing apparatus 500 can form a low-temperature plasma reaction layer by discharge between the two dielectrics 13 by applying a voltage between the application electrode 11 and the ground electrode 12 using the high-voltage power supply 14. it can. In FIG. 4, both the application electrode 11 and the ground electrode 12 are laminated in close contact with the dielectric 13, but only one of the dielectrics 13 may be provided.

In the gas processing apparatus 500 of this embodiment, the application electrode 11, the ground electrode 12, and the dielectric 13 have a non-breathable structure through which the gas to be processed does not pass. For this reason, the gas to be processed supplied from one of the circular end faces (in the direction of arrow a in FIG. 3) to the plasma generating section passes through the low-temperature plasma reaction layer formed between the two dielectrics 13, It discharges | emits from the other end surface side (arrow b direction of FIG. 3). That is, a flow path constituted by a low temperature plasma reaction layer formed between the two dielectrics 13 is formed in the plasma generation unit. In the flow path formed in the low-temperature plasma reaction layer, a catalyst film 100 that is separated from the two dielectrics 13 is disposed. For this reason, the to-be-processed gas which flows through a low-temperature plasma reaction layer can pass the catalyst body film | membrane 100 via a mesopore. Accordingly, the component to be processed in the gas to be processed is oxidized and decomposed by the function of the catalyst body film 100 on which plasma acts, as in the first to third embodiments. In FIG. 4, a space is formed between the catalyst body film 100 and the two dielectrics 13. Further, the catalyst body film 100 may be in close contact with one dielectric 13 or may not be in close contact.

As in the gas processing apparatus 500 of the present embodiment, an annual ring-shaped multilayer structure may be used, and the multilayer structure makes it easy to secure a flow path. For this reason, it becomes easy to increase the amount of gas to be processed, and a large amount of components to be processed can be efficiently decomposed. The gas processing apparatus 500 has a plurality of cylindrical annual rings of the catalyst body film 100 so that the processing target gas can be efficiently oxidized and decomposed according to the amount of components to be processed and the use conditions such as the flow rate. But even one can be set arbitrarily.

Here, in the gas processing apparatus according to the first to fourth embodiments, when a component contained in the gas to be processed is processed, the power source 14 applies a voltage to the application electrode 11 and the component containing the component is processed. Gas is supplied to the flow path. As a result, components in the gas to be processed that flow through the flow path and reach the mesopores are oxidized and decomposed at room temperature without being heated by the catalyst body film 100. Furthermore, components in the gas to be treated may be oxidized and decomposed by plasma. Further, if only the catalyst body film 100 is used, the surface of the catalyst body film 100 (gold catalyst particles) may be poisoned due to contact with components, and the catalytic activity may be lost, or a reaction intermediate such as formaldehyde may be generated. However, when the plasma is used in combination, the surface of the catalyst film 100 is cleaned and the catalytic activity is maintained for a longer period. Moreover, there is almost no production amount of a reaction intermediate, and decomposition of harmful components due to oxidation can be maintained for a longer period.

In the gas processing apparatus 200 of the first embodiment, the application electrode 11 has been described as being arranged on the upstream side in the gas flow direction. However, the present invention is not limited to this, and the gas may flow from the ground electrode 12 side.

The gas processing apparatuses of the first to fourth embodiments described above can suppress the generation of reaction intermediates by the combination of the catalyst body film 100 and plasma, and at the same time, the catalyst body film 100 (gold catalyst particles) during the decomposition process. ), The catalyst body film 100 is cleaned by plasma, so that the catalytic activity of the catalyst body film 100 can be maintained for a longer period of time. Therefore, according to the gas processing apparatus of the first to fourth embodiments, it is possible to realize a gas processing apparatus capable of oxidizing and decomposing a target compound for a longer period of time.

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples.

[Example 1]
Into a beaker, 5.2 g of tetraethoxysilane (TEOS) was added, and 6.0 g of ethanol was further added. To this was further added 2.7 g of 0.01M hydrochloric acid, and the mixture was stirred at room temperature for 20 minutes (solution A). To another beaker, 1.38 g of a nonionic surfactant (Pluronic P123) and 2.62 g of ethanol were added and stirred at room temperature for 30 minutes (solution B). The solution B was added to the solution A and mixed at room temperature, followed by further stirring for 3 hours to prepare a precursor solution of mesoporous silica. The solvent of the precursor solution was distilled off, and the resulting solid was dried and pulverized to obtain a powdery support.
The powdery support was put into a solution containing diammine dinitroplatinum nitrate and stirred. The powder was filtered from the solution, dried at 300 ° C. for 3 hours, and then calcined in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas for 1 hour at 250 ° C. to obtain a Pt / mesoporous silica powder. The amount of Pt supported on the mesoporous silica film was 1 wt%.
When the Pt / mesoporous silica powder was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 377 m ² / g, 0.52 cm ^{3 /} g, and 7.0 nm, respectively. When the particle size of Pt was observed by TEM, it was 3.2 nm.

In addition, the existence of a Pt / mesoporous silica powder communication structure was confirmed by three-dimensional tomography in which electron microscopic images from various angles of the catalyst body were reconstructed into three-dimensional images. A part of the reconstructed stereoscopic image is shown in FIGS. 5, 6 and 7 (taken at an inclination angle of 60 to −50 °, 1 ° step). The position and shape of the oxidation catalyst particles (clearly colored dots) and mesopores (dark areas around the oxidation catalyst particles) in each photo are different, and the mesopores are not cylinder-shaped. It was confirmed that it has a communication structure in which multiple mesopores are connected.
In addition, since the catalyst bodies of the other examples were produced by the same method as in Example 1 and it was confirmed that the catalytic activity was maintained for a longer time in the test examples shown below, the Examples It can be understood that the communication structure is the same as in FIG.

[Example 2]
Pd / mesoporous silica powder was obtained in the same manner as in Example 1 except that palladium chloride was used instead of diammine dinitroplatinum nitrate. When the particle size of Pd was observed by TEM, it was 3.0 nm.

[Example 3]
A catalyst body of platinum iron alloy / mesoporous silica powder was obtained in the same manner as in Example 1 except that iron (III) chloride was further dissolved in a solution containing diammine dinitroplatinum nitrate. When the particle size of the Pt / Fe alloy was observed by TEM, it was 3.6 nm.
[Example 4]
Into a beaker, 5.2 g of tetraethoxysilane (TEOS) was added, and 6.0 g of ethanol was further added. To this was further added 2.7 g of 0.01M hydrochloric acid, and the mixture was stirred at room temperature for 20 minutes (solution A). To another beaker, 1.38 g of a nonionic surfactant (Pluronic (registered trademark, hereinafter the same) P123) and 2.62 g of ethanol were added and stirred at room temperature for 30 minutes (solution B). Then, B liquid was added to A liquid, mixed under room temperature conditions, and further stirred for 3 hours to obtain a precursor solution of mesoporous silica. A ceramic honeycomb (manufactured by Iwatani Corporation) was immersed in the mesoporous silica precursor solution, and the pressure was reduced for 15 minutes. Thereafter, the ceramic honeycomb was pulled up and the excess solution was removed by air blowing, then heated at 1 ° C./min and fired at 450 ° C. for 4 hours to obtain a ceramic honeycomb having a fixed mesoporous silica film.
After that, the ceramic honeycomb with the mesoporous silica film fixed thereon was immersed in a solution containing diamine dinitroplatinum nitrate, and the excess solution was removed by air blowing. After drying at 300 ° C. for 3 hours, firing was performed at 250 ° C. for 1 hour in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas to obtain a Pt / mesoporous silica film / honeycomb. The supported amount of Pt with respect to the mesoporous silica film (including the particles (including Pt particles in the case of Example 1)) is 1 wt%.
When the Bt method was used for the Pt / mesoporous silica film / honeycomb, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 377 m ² / g, 0.52 cm ^{3 /} g, and 7.0 nm, respectively. . The mesoporous silica film had a thickness of 500 nm. Moreover, when the particle size of Pt was observed with TEM, it was 3.2 nm.
[Example 5]
A Pt / mesoporous silica film / honeycomb was obtained in the same manner as in Example 4 except that 1.3 g of mesitylene was further added to the B liquid. The amount of Pt supported on the mesoporous silica film was 1 wt%.
When the Pt / mesoporous silica film / honeycomb was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 401 m ² / g, 0.64 cm ³ / g, and 20 nm, respectively. The mesoporous silica film had a thickness of 500 nm. Moreover, when the particle size of Pt was observed with TEM, it was 12 nm.

[Example 6]
10.4 g of tetraethoxysilane (TEOS) was put in a beaker, and 12.0 g of ethanol was further added. To this, 4.5 g of 0.01M hydrochloric acid was further added and stirred at room temperature for 20 minutes (solution A). To another beaker, 2.9 g of a nonionic surfactant (Brij (registered trademark) 56) and 8.0 g of ethanol were added and stirred at room temperature for 30 minutes (liquid B). Then, B liquid was added to A liquid, mixed under room temperature conditions, and further stirred for 3 hours to obtain a precursor solution of mesoporous silica. A ceramic honeycomb (manufactured by Iwatani Corporation) was immersed in the mesoporous silica precursor solution, and the pressure was reduced for 15 minutes. The ceramic honeycomb was pulled up and the excess solution was removed by air blowing. Then, the temperature was raised at 1 ° C./min and fired at 450 ° C. for 4 hours to obtain a ceramic honeycomb having a fixed mesoporous silica film.
Thereafter, the ceramic honeycomb with the mesoporous silica film fixed thereto was immersed in a solution containing diamine dinitroplatinum nitrate solution, and the excess solution was removed by air blowing. After drying at 300 ° C. for 3 hours, firing was performed at 250 ° C. for 1 hour in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas to obtain a Pt / mesoporous silica film / honeycomb. The amount of Pt supported on the mesoporous silica film was 1 wt%.
When the BET method was used for the Pt / mesoporous silica film / honeycomb, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 380 m ² / g, 0.38 cm ^{3 /} g, and 4.5 nm, respectively. . The mesoporous silica film had a thickness of 500 nm. Moreover, when the particle size of Pt was observed with TEM, it was 3.2 nm.
[Example 7]
A Pt / mesoporous silica film / honeycomb was obtained in the same manner as in Example 6 except that 1.3 g of mesitylene was further added to the B liquid. The amount of Pt supported on the mesoporous silica film was 1 wt%.
When the Pt / mesoporous silica film / honeycomb was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 365 m ² / g, 0.44 cm ³ / g, and 12 nm, respectively. The mesoporous silica film had a thickness of 500 nm. Moreover, when the particle size of Pt was observed with TEM, it was 3.2 nm.

[Example 8]
Into a beaker, 6.2 g of tetraethoxysilane (TEOS) was added, and 4.8 g of ethanol was further added. To this, 2.2 g of 0.01M hydrochloric acid was further added and stirred at room temperature for 20 minutes (solution A). To another beaker, 1.53 g of a cationic surfactant (hexadecyltrimethylammonium bromide, CTAB) and 2.2 g of 0.01M hydrochloric acid were added and stirred at room temperature for 30 minutes (solution B). Then, B liquid was added to A liquid, mixed under room temperature conditions, and further stirred for 3 hours to obtain a precursor solution of mesoporous silica. A ceramic honeycomb (manufactured by Iwatani Corporation) was immersed in the mesoporous silica precursor solution, and the pressure was reduced for 15 minutes. Thereafter, the ceramic honeycomb was pulled up and the excess solution was removed by air blowing, then heated at 1 ° C./min and fired at 450 ° C. for 4 hours to obtain a ceramic honeycomb having a fixed mesoporous silica film.
After that, the ceramic honeycomb with the mesoporous silica film fixed thereon was immersed in a solution containing diamine dinitroplatinum nitrate, and the excess solution was removed by air blowing. After drying at 300 ° C. for 3 hours, firing was performed at 250 ° C. for 1 hour in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas to obtain a Pt / mesoporous silica film / honeycomb. The amount of Pt supported on the mesoporous silica film was 1 wt%.
When the BET method was used for the Pt / mesoporous silica film / honeycomb, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 341 m ² / g, 0.50 cm ^{3 /} g, and 2.43 nm, respectively. . The mesoporous silica film had a thickness of 500 nm. Moreover, when the particle size of Pt was observed with TEM, it was 2.0 nm.

[Example 9]
A Pd / mesoporous silica membrane / honeycomb was obtained in the same manner as in Example 4 except that palladium chloride was used instead of diammine dinitroplatinum nitrate. The amount of Pt supported on the mesoporous silica film was 1 wt%.
When the Pd / mesoporous silica film / honeycomb was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 377 m ² / g, 0.52 cm ³ / g, and 7 nm, respectively. The mesoporous silica film had a thickness of 500 nm. Further, when the particle size of Pd was observed by TEM, it was 3.0 nm.

[Example 10]
A Pd / mesoporous silica membrane / honeycomb was obtained in the same manner as in Example 6 except that palladium chloride was used instead of diammine dinitroplatinum nitrate. The amount of Pt supported on the mesoporous silica film was 1 wt%.
When the Pd / mesoporous silica film / honeycomb was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 380 m ² / g, 0.38 cm ^{3 /} g, and 4.5 nm, respectively. . The mesoporous silica film had a thickness of 500 nm. Further, when the particle size of Pd was observed by TEM, it was 3.0 nm.

[Example 11]
A Pd / mesoporous silica membrane / honeycomb was obtained in the same manner as in Example 8 except that palladium chloride was used instead of diammine dinitroplatinum nitrate. The amount of Pt supported on the mesoporous silica film was 1 wt%.
When the Pd / mesoporous silica film / honeycomb was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 341 m ² / g, 0.5 cm ^{3 /} g, and 2.43 nm, respectively. . The mesoporous silica film had a thickness of 500 nm. Moreover, when the particle size of Pd was observed with TEM, it was 2.0 nm.

[Example 12]
A platinum oxide / mesoporous silica film / honeycomb was obtained in the same manner as in Example 4 except that the firing treatment was not performed in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas. The amount of platinum oxide supported on the mesoporous silica film was 1 wt%.
The platinum oxide / mesoporous silica film / honeycomb was measured by the BET method. The specific surface area, pore volume, and pore diameter of the mesoporous silica film were 377 m ² / g, 0.52 cm ³ / g, and 7 nm, respectively. . The mesoporous silica film had a thickness of 500 nm. Moreover, it was 3.2 nm when the particle size of the platinum oxide was observed with TEM.

[Example 13]
Palladium oxide / mesoporous silica was prepared in the same manner as in Example 4 except that palladium chloride was used in place of diammine dinitroplatinum nitrate and no calcination treatment was performed in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas. A membrane / honeycomb was obtained. The amount of palladium oxide supported on the mesoporous silica film was 1 wt%.
The palladium oxide / mesoporous silica membrane / honeycomb was measured by the BET method. The specific surface area, pore volume, and pore diameter of the mesoporous silica membrane were 377 m ² / g, 0.52 cm ³ / g, and 7 nm, respectively. . The mesoporous silica film had a thickness of 500 nm. Moreover, when the particle size of palladium oxide was observed with TEM, it was 3.0 nm.

[Comparative Example 1]
To 10 g of mesoporous silica having a cylindrical nanopore structure (ALDRICH, MCM-41), a diamminedinitroplatinum nitrate solution corresponding to 1 wt% of Pt was mixed, and evaporated to dryness by heating. Furthermore, the obtained solid content was dried under reduced pressure for 12 hours. Thereafter, the obtained solid content was calcined in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas for 1 hour at 250 ° C. to prepare Pt / mesoporous silica catalyst particles. Then, it shape | molded using the binder and produced what granulated the Pt / mesoporous silica catalyst particle.
When BET measurement was performed, the specific surface area, pore volume, and pore diameter of mesoporous silica were 760 m ² / g, 0.84 cm ^{3 /} g, and 3.7 nm, respectively. Moreover, when the particle size of Pt was observed with TEM, it was 3.1 nm.

[Comparative Example 2]
The Pt / mesoporous silica catalyst particles were granulated in the same manner as in Comparative Example 1 except that mesoporous silica (ALDRICH, SBA-15) having a cylindrical nanopore structure was used instead of mesoporous silica (ALDRICH, MCM-41). What was shape | molded in the shape was obtained.
When BET measurement was performed, the specific surface area, pore volume, and pore diameter of mesoporous silica were 635 m ² / g, 1.07 cm ^{3 /} g, and 6.3 nm, respectively. Moreover, when the particle size of Pt was observed with TEM, it was 6.0 nm.

[Comparative Example 3]
A Pd / mesoporous silica catalyst particle formed into granules was obtained in the same manner as in Comparative Example 1 except that palladium chloride was used instead of diammine dinitroplatinum nitrate. Further, when the particle size of Pd was observed by TEM, it was 3.0 nm.

[Comparative Example 4]
A Pd / mesoporous silica catalyst particle was formed into granules by the same method as in Comparative Example 2 except that palladium chloride was used instead of diammine dinitroplatinum nitrate. Moreover, when the particle size of Pd was observed with TEM, it was 6.0 nm.

[Comparative Example 5]
Titanium isopropoxide (hereinafter referred to as “TTIP”) is mixed with isopropyl alcohol (hereinafter referred to as “IPA”) as a dispersion medium and hydrochloric acid as a catalyst, and then a predetermined amount of water is added, and then at about 4 ° C. for 1 hour. Hydrolyzed. The composition ratio (molar ratio) of the starting solution was TTIP / IPA / water / hydrochloric acid = 1/140/4 / 0.4. A titanium dioxide colloidal sol was prepared by allowing to stand at room temperature for 10 hours after hydrolysis. Thereafter, a ceramic honeycomb (manufactured by Iwatani Corporation) was immersed in the titanium dioxide colloid sol, and the pressure was reduced for 15 minutes. Thereafter, the ceramic honeycomb was pulled up, and the excess solution was removed by air blowing. Then, the temperature was raised at 1 ° C./min and fired at 450 ° C. for 4 hours to obtain a ceramic honeycomb in which the titanium dioxide film was fixed.
Then, after immersing in a solution containing diamine dinitroplatinum nitrate solution in a ceramic honeycomb to which a titanium dioxide film is fixed, and removing the excess solution by air blowing, in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas Firing at 250 ° C. for 1 hour gave a Pt / titanium dioxide film / honeycomb. The amount of Pt supported on the titanium dioxide film was 1 wt%.
When the BET method was used to measure Pt / titanium dioxide film / honeycomb, the specific surface area, pore volume, and pore diameter of the mesoporous silica film were 100 m ² / g, 0.10 cm ^{3 /} g, and 5.0 nm, respectively. . The mesoporous silica film had a thickness of 1000 nm. Moreover, when the particle size of Pt was observed with TEM, it was 3.0 nm.

[Example 14]
To 0.2 g of the surfactant (Pluronic P123), 3.55 mL of ethanol was added, and the mixture was stirred for 20 minutes or more and dissolved to obtain Liquid A. To 0.63 mL of hydrochloric acid, 1.05 g of tetraisopropyl orthotitanate (TTIP) was added and stirred for 5 minutes to obtain solution B.
The A liquid was added to the B liquid and further stirred for 15 minutes to obtain a precursor solution of mesoporous titanium oxide.
The solvent was distilled off from the precursor solution, and the resulting solid was pulverized in an electric furnace at 450 ° C. for 4 hours to obtain a powdery support.
A predetermined concentration of aqueous chloroauric acid solution was placed in a beaker and heated to 70 ° C. in a water bath. The pH was adjusted to 7 by slowly adding 0.1 M aqueous sodium hydroxide solution. The aqueous chloroauric acid solution was cooled to room temperature, the above powder support was added, and the mixture was heated to 70 ° C. and stirred for 1 hour after reaching 70 ° C. The powder was filtered off from the solution and washed 5 times with pure water. Firing was carried out at 300 ° C. for 2 hours in an electric furnace to obtain Au-supported mesoporous titanium oxide powder.
When the amount of Au supported on the Au-supported mesoporous titanium oxide powder was measured by atomic absorption, the amount of Au supported on the mesoporous titanium oxide powder was 20% by mass. When the Au-supported mesoporous titanium oxide powder was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous titanium oxide powder were 118 m ^{2 /} g, 0.54 g / cm ³ , and 9.23 nm, respectively. there were. Moreover, when the particle diameter of Au was observed with TEM, it was 2.4 nm.

[Example 15]
The same as in Example 14 except that 0.286 mL of acetic acid and 0.1 mL of pure water were added to 16.7 g of 2.5% iron (III) isopropoxide / isopropanol solution, and the mixture was stirred for 10 minutes to obtain solution B. Thus, Au-supported iron oxide powder was obtained. When the amount of Au supported on the Au-supported iron oxide powder was measured by atomic absorption, the amount of Au supported on the mesoporous titanium oxide powder was 20% by mass. The specific surface area, pore volume, and pore diameter of the mesoporous iron oxide powder were 351 m ^{2 /} g, 0.48 g / cm ³ , and 6.20 nm, respectively. Moreover, when the particle diameter of Au was observed with TEM, it was 3.3 nm.

[Example 16]
A catalyst body of gold-iron alloy / mesoporous titanium oxide powder was obtained in the same manner as in Example 14, except that iron (III) chloride was further dissolved in a chloroauric acid aqueous solution. When the particle size of the Au / Fe alloy was observed with TEM, it was 3.8 nm.

[Example 17]
(Ti plate fixed with Au-supported mesoporous titanium oxide film)
To 0.2 g of the surfactant (Pluronic P123), 3.55 mL of ethanol was added, and the mixture was stirred for 20 minutes or more and dissolved to obtain Liquid A. To 0.63 mL of hydrochloric acid, 1.05 g of tetraisopropyl orthotitanate (TTIP) was added and stirred for 5 minutes to obtain solution B.
The A liquid was added to the B liquid and further stirred for 15 minutes to obtain a precursor solution of mesoporous titanium oxide. Thereafter, a precursor solution of mesoporous titanium oxide was used, and a film was formed on a titanium (hereinafter referred to as Ti) plate at a rotational speed of 3000 rpm using a spin coater. The formed Ti plate was placed in a petri dish and allowed to stand for 2 hours in a −20 ° C., 20% RH environment (freezer). After removing from the freezer and returning to room temperature, the petri dish lid was opened and the Ti plate was taken out. Firing was performed at 450 ° C. for 4 hours in an electric furnace to obtain a Ti plate on which a mesoporous titanium oxide film (film-like support) was fixed. In firing, the temperature rise and fall were 1 ° C. per minute.
A predetermined concentration of aqueous chloroauric acid solution was placed in a beaker and heated to 70 ° C. in a water bath. The pH was adjusted to 7 by slowly adding 0.1 M aqueous sodium hydroxide solution. The aqueous chloroauric acid solution was cooled to room temperature, immersed in a Ti plate on which a mesoporous titanium oxide film was fixed, and deaerated by reducing the pressure for about 15 minutes. The mixture was again heated to 70 ° C. in a water bath, and stirred for 1 hour after reaching 70 ° C. The Ti plate on which the mesoporous titanium oxide film was fixed was taken out, washed 5 times with pure water, and excess water was removed with a waste cloth. Firing was performed at 300 ° C. for 2 hours in an electric furnace to obtain a Ti plate on which the Au-supporting mesoporous titanium oxide film was fixed.
When the cross section of the Au-supporting mesoporous titanium oxide film was observed with a TEM, the film thickness was 100 nm. Further, when the amount of Au supported was measured by atomic absorption, the amount of Au supported on the mesoporous titanium oxide film was 20% by mass. When the Ti plate on which the Au-supporting mesoporous titanium oxide film was immobilized was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous titanium oxide film were 118 m ^{2 /} g, 0.54 g / cm ³ , respectively. It was 9.23 nm. Moreover, when the particle diameter of Au was observed with TEM, it was 2.4 nm.

[Example 18]
(Ti plate fixed with Au-supported mesoporous titanium oxide film)
A Ti plate on which the Au-supported mesoporous titanium oxide film was immobilized was obtained in the same manner as in Example 17 except that the mesoporous titanium oxide film was immobilized on the Ti plate at a firing temperature of 300 ° C.
When the cross section of the Au-supporting mesoporous titanium oxide film was observed with a TEM, the film thickness was 100 nm. Moreover, when measured by atomic absorption, the amount of Au supported on the mesoporous titanium oxide film was 30% by mass. When the Ti plate on which the Au-supporting mesoporous titanium oxide film was immobilized was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous titanium oxide film were 206 m ^{2 /} g and 0.34 g / cm ³ , respectively. 3.71 nm. Moreover, when the particle diameter of Au was observed with TEM, it was 2.4 nm.

[Example 19]
(Ti plate fixed with Au-supported mesoporous zirconium oxide film)
1 mL of ethanol was added to 0.2 g of a surfactant (Pluronic P123), and the mixture was stirred for 20 minutes to obtain solution A. To 0.58 g of zirconium (IV) propoxide (Zr (OPr) ₄ ), 0.286 mL of acetic acid and 0.1 mL of pure water were added and stirred for 10 minutes to obtain a liquid B.
After liquid A was added to liquid B, 0.093 mL of hydrochloric acid was added and stirred for 1 hour to obtain a precursor solution of mesoporous zirconium oxide.
Thereafter, a precursor solution of mesoporous zirconium oxide was used, and a film was formed on a Ti plate at a rotational speed of 3000 rpm using a spin coater. The formed Ti plate was placed in a petri dish and allowed to stand for 2 hours in a −20 ° C., 20% RH environment (freezer). After removing from the freezer and returning to room temperature, the petri dish lid was opened and the Ti plate was taken out. Firing was performed at 450 ° C. for 4 hours in an electric furnace to obtain a Ti plate on which a mesoporous zirconium oxide film (film-like support) was fixed. In firing, the temperature rise and fall were 1 ° C. per minute.
A predetermined concentration of aqueous chloroauric acid solution was placed in a beaker and heated to 70 ° C. in a water bath. The pH was adjusted to 7 by slowly adding 0.1 M aqueous sodium hydroxide solution. The aqueous chloroauric acid solution was cooled to room temperature, immersed in a Ti plate on which a mesoporous zirconium oxide film was immobilized, and degassed by reducing the pressure for about 15 minutes. The mixture was again heated to 70 ° C. in a water bath, and stirred for 1 hour after reaching 70 ° C. The Ti plate on which the mesoporous zirconium oxide film was fixed was taken out, washed 5 times with pure water, and excess water was removed with a waste cloth. Firing was performed at 300 ° C. for 2 hours in an electric furnace to obtain a Ti plate on which the Au-supported mesoporous zirconium oxide film was immobilized.
When the cross section of the Au-supporting mesoporous zirconium oxide film was observed with a TEM, the film thickness was 150 nm. Further, when measured by atomic absorption, the amount of Au supported on the mesoporous zirconium oxide film was 10.6% by mass. When the Ti plate on which the Au-supported mesoporous zirconium oxide film was fixed was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous zirconia film were 85.2 m ^{2 /} g and 0.29 g / cm, respectively. ³ and 6.18 nm. Moreover, when the particle diameter of Au was observed with TEM, it was 2.5 nm.

[Example 20]
(Ti plate fixed with Au-supported mesoporous zirconium oxide film)
A Ti plate having an Au-supported mesoporous zirconium oxide film immobilized thereon was obtained in the same manner as in Example 19 except that the mesoporous zirconium oxide film was immobilized on a Ti plate at a firing temperature of 300 ° C.
When the cross section of the Au-supporting mesoporous zirconium oxide film was observed with a TEM, the film thickness was 150 nm. Further, when measured by atomic absorption, the amount of Au supported on the mesoporous zirconium oxide film was 18.2% by mass. When the Ti plate on which the Au-supported mesoporous zirconium oxide film was immobilized was measured by the BET method, the specific surface area, pore volume, and pore diameter of the mesoporous zirconium oxide film were 94.3 m ^{2 /} g and 0.42 g / cm, respectively. ³ and 4.19 nm. Moreover, when the particle diameter of Au was observed with TEM, it was 2.5 nm.

[Comparative Example 6]
A Ti plate having an Au-supported titanium oxide film immobilized thereon was obtained in the same manner as in Example 17 except that the precursor solution was prepared without using a surfactant (Pluronic P123).
When the cross section of the Au-supported titanium oxide film was observed with a TEM, the film thickness was 100 nm. Further, when measured by atomic absorption, the amount of Au supported on the titanium oxide film was 6.6% by mass. When the Ti plate on which the Au-supported titanium oxide film was immobilized was measured by the BET method, the specific surface area of the titanium oxide film was 10 m ² / g, and it was confirmed that this titanium oxide film did not have a mesoporous structure. It was done. Further, when the particle diameter of Au was observed by TEM, it was 5 nm.

[Comparative Example 7]
A Ti plate having an Au-supported zirconium oxide film immobilized thereon was obtained in the same manner as in Example 19 except that a precursor solution was prepared without using a surfactant (Pluronic P123).
When the cross section of the Au-supported zirconium oxide film was observed with a TEM, the film thickness was 150 nm. Further, when measured by atomic absorption, the amount of Au supported on the zirconium oxide film was 5% by mass. When the Ti plate on which the Au-supported zirconium oxide film was immobilized was measured by the BET method, the specific surface area of the titanium oxide film was 7.9 m ² / g, and this titanium oxide film does not have a mesoporous structure. Was confirmed. Further, when the particle diameter of Au was observed by TEM, it was 5 nm.

[Comparative Example 8]
470 mg of Au (I) (TPP) Cl complex was added to 20 mL of ethanol and stirred for 30 minutes. 35.9 mg of sodium borohydride was dissolved in 7.5 mL of ethanol, and this was added to the above solution all at once and stirred for 3 hours. To this, 500 mL of hexane was added and allowed to stand for 24 hours. Further, it was filtered, washed several times with hexane and dried to obtain gold protected with triphenylphosphine. Gold protected with triphenylphosphine was dissolved in 24 mL of dichloromethane, 1 g of mesoporous silica (SBA-15) was added, and the mixture was stirred for 2 hours. After stirring, the mixture was filtered, and calcined at 200 ° C. to obtain mesoporous silica carrying Au. The obtained Au-supported mesoporous silica is suspended in water, formed on a Ti plate at a rotational speed of 3000 rpm using a spin coater, and dried to obtain a Ti plate on which Au-supported mesoporous silica is fixed. It was.
When the cross section of the Au-supported mesoporous silica was observed with a TEM, the film thickness was 100 nm. Further, when measured by atomic absorption, the amount of Au supported on mesoporous silica was 1% by mass. When Au-supported mesoporous silica was measured by the BET method, the specific surface area, pore volume, and pore diameter were 871 m ² / g, 1.13 cm ^{3 /} g, and 7.5 nm, respectively. Further, when the particle diameter of Au was observed by TEM, it was 0.8 nm.

[Ethylene degradation test]
Using the catalyst bodies of Examples 1 to 13 and Comparative Examples 1 to 5, ethylene was decomposed. The reaction gas was prepared by mixing air containing 10 ppm of ethylene and room air, and the flow rate of each gas was controlled by a thermal mass flow controller. For analysis of the reaction gas, an infrared spectrophotometer (FTIR-6000, manufactured by JASCO Corporation) equipped with a gas cell having a long optical path (20 m) was used. The reaction conditions were an ethylene concentration of 0.5 ppm, an oxygen concentration of 20%, a gas flow rate of 1 L / min, a reaction temperature of 5 ° C., and a relative humidity of 90%.
The ethylene removal rate was determined from the following equation.
Ethylene removal rate (%) = {(initial ethylene concentration−ethylene concentration after reaction) / initial ethylene concentration} × 100
The obtained results are shown in Table 1.

As can be understood from the above results, Comparative Examples 1 and 2 showed 8.4% removal rate of ethylene after 1 day, but decreased to 4.7% and 3.0% after 7 days. In Comparative Examples 3 to 5, the removal rate was zero after one day. On the other hand, it was confirmed that the ethylene removal rates of Examples 1 to 13 were not drastically lowered after 1 day and after 7 days.

From the above, the examples can decompose and remove hydrocarbons such as ethylene at a low concentration of about 0.5 ppm at a temperature of 5 ° C., which is lower than room temperature, which is generally considered, and the degradation activity thereof is unlikely to occur. It was shown that it can be used.

(Carbon monoxide removal test using a low-temperature plasma reactor (gas treatment device) (Test Examples 1 to 14))
As the gas processing apparatus, a gas processing apparatus 300 according to the second embodiment shown in FIG. 2 was prepared. As the catalyst body 100, Ti plates obtained in Examples 17 to 20 and Comparative Examples 6 to 8 were used, respectively. A copper tape was used as the application electrode 11 and the installation electrode 12. As the dielectric 13, α-alumina was used.

For plasma generation, a plasma generation power source was used to connect the application electrode 11 and the ground electrode 12 to the plasma generation power source, and plasma was generated by applying a voltage. The applied voltage was 8 kVp-p, and the discharge output was 0.1 W.

Using carbon monoxide (CO), the oxidation reaction of the gas treatment apparatus 300 in which the Ti plates of Examples and Comparative Examples were used was evaluated. Specifically, carbon monoxide (concentration: 1,000 ppm) and air are mixed to prepare a gas to be processed, and the gas to be processed is flowed (between two dielectrics 13) while controlling the flow rate with a mass flow controller. Supplied to.

Analysis of the gas to be processed before and after the treatment by the gas processing apparatus 300 uses an infrared spectrophotometer (FTIR-6000, manufactured by JASCO Corporation) equipped with a gas cell having a long optical path (2.5 m). It was. The reaction conditions were a carbon monoxide concentration of 1,000 ppm, an oxygen concentration of 20%, a relative humidity of 50%, a gas flow rate of 0.1 L / min, a catalyst size of 25 cm ² , and a reaction temperature of room temperature.

Test Examples 1 to 14 were performed while changing the catalyst body to be used and changing the presence or absence of plasma generation.
Using the infrared spectrophotometer described above, the CO concentration (hereinafter also referred to as “initial CO concentration”) in the gas to be processed before being supplied to the gas processing device 300, and the target after being processed by the gas processing device 300 The CO concentration in the process gas (hereinafter also referred to as “post-reaction CO concentration”) was measured, and the CO removal rate was calculated using the following equation. In addition, the time which processed the to-be-processed gas with the gas processing apparatus 300 is shown in Table 3 and Table 4 mentioned later.
CO removal rate (%) = {(initial CO concentration−post-reaction CO concentration) / initial CO concentration} × 100

(Test Example 1)
Using the Ti plate obtained in Example 17, a CO removal test was performed without generating plasma.

(Test Example 2)
A CO removal test was performed in the same manner as in Test Example 1 except that the Ti plate obtained in Example 18 was used.

(Test Example 3)
A CO removal test was performed in the same manner as in Test Example 1 except that the Ti plate obtained in Example 19 was used.

(Test Example 4)
A CO removal test was performed in the same manner as in Test Example 1 except that the Ti plate obtained in Example 20 was used.

(Test Example 5)
A CO removal test was performed in the same manner as in Test Example 1 except that the Ti plate obtained in Comparative Example 6 was used.

(Test Example 6)
A CO removal test was performed in the same manner as in Test Example 1 except that the Ti plate obtained in Comparative Example 7 was used.

(Test Example 7)
A CO removal test was performed in the same manner as in Test Example 1 except that the Ti plate obtained in Comparative Example 8 was used.

(Test Example 8)
Using the Ti plate obtained in Example 17, a plasma with a discharge power of 0.1 W was generated and a CO removal test was performed.

(Test Example 9)
A CO removal test was performed in the same manner as in Test Example 8 except that the Ti plate obtained in Example 18 was used.

(Test Example 10)
A CO removal test was performed in the same manner as in Test Example 8 except that the Ti plate obtained in Example 19 was used.

(Test Example 11)
A CO removal test was performed in the same manner as in Test Example 8, except that the Ti plate obtained in Example 20 was used.

(Test Example 12)
A CO removal test was performed in the same manner as in Test Example 8 except that the Ti plate obtained in Comparative Example 6 was used.

(Test Example 13)
A CO removal test was performed in the same manner as in Test Example 8 except that the Ti plate obtained in Comparative Example 7 was used.

(Test Example 14)
A CO removal test was performed in the same manner as in Test Example 8 except that the Ti plate obtained in Comparative Example 8 was used.

Table 2 shows the CO removal rates in Test Examples 1 to 14. *

[Carbon monoxide removal test (Test Examples 15 to 17)]
Using the powder catalyst bodies of Example 14 (Test Example 15), Example 15 (Test Example 16), and Example 16 (Test Example 17), carbon monoxide was decomposed in Test Examples 15 to 17. It was.
Carbon monoxide and air were mixed to prepare a test gas having a carbon monoxide concentration of 1,000 ppm, and the flow rate was controlled by a mass flow controller and supplied to the catalyst body. For the analysis of the gas to be processed before treatment and the gas to be treated after 1 hour of treatment, an infrared spectrophotometer (FTIR-6000, manufactured by JASCO Corporation) equipped with a gas cell having a long optical path (2.5 m) was used. The reaction conditions were a carbon monoxide concentration of 1,000 ppm, an oxygen concentration of 20%, a relative humidity of 60%, a gas flow rate of 1.0 L / min, and a reaction temperature of room temperature.
The CO removal rate was calculated using the following equation, and the results are shown in Table 3.
CO removal rate (%) = {(initial CO concentration−post-reaction CO concentration) / initial CO concentration} × 100

[Ammonia removal test using low-temperature plasma reactor (gas treatment device) (Test Examples 18 and 19)]
The same gas treatment apparatus as in the carbon monoxide removal test (Test Examples 1 to 14) using a low-temperature plasma reactor (gas treatment apparatus) was used. Further, Ti plates obtained in Example 19 and Comparative Example 8 were used for the catalyst body 100, respectively.
A carbon monoxide removal test (Test Examples 1 to 14) using a low-temperature plasma reactor (gas treatment device), except that nitrogen gas containing 10,000 ppm of ammonia and indoor air were prepared and used. The same was done. For analysis of the reaction gas, an infrared spectrophotometer (FTIR-6000, manufactured by JASCO Corporation) equipped with a gas cell having a long optical path (2.5 m) was used. The reaction conditions were an ammonia concentration of 5 ppm, an oxygen concentration of 20%, a relative humidity of 50%, a gas flow rate of 0.1 L / min, a catalyst amount of 25 cm ³ , and a reaction temperature of room temperature.
The ammonia removal rate was calculated using the following formula, and the results are shown in Table 4.
Ammonia removal rate (%) = {(initial ammonia level−post-reaction ammonia concentration) / initial ammonia concentration} × 100

(Test Example 18)
Using the Ti plate obtained in Example 19, plasma with a discharge power of 0.1 W was generated and an ammonia removal test was performed.

(Test Example 19)
An ammonia removal test was performed in the same manner as in Test Example 18 except that the Ti plate obtained in Comparative Example 8 was used.

[Trimethylamine removal test using low-temperature plasma reactor (gas treatment device) (Test Examples 20 and 21)]
The same gas treatment apparatus as in the carbon monoxide removal test (Test Examples 1 to 14) using a low-temperature plasma reactor (gas treatment apparatus) was used. Further, Ti plates obtained in Example 19 and Comparative Example 8 were used for the catalyst body 100, respectively.
The reaction gas was prepared by using nitrogen gas containing 10,000ppm of trimethylamine and room air to prepare the reaction gas, and the carbon monoxide removal test using a low-temperature plasma reactor (gas treatment device) (test example) 1 to 14). For analysis of the reaction gas, an infrared spectrophotometer (FTIR-6000, manufactured by JASCO Corporation) equipped with a gas cell having a long optical path (2.5 m) was used. The reaction conditions were a trimethylamine concentration of 10 ppm, an oxygen concentration of 20%, a relative humidity of 50%, a gas flow rate of 0.1 L / min, a catalyst amount of 25 cm ³ , and a reaction temperature of room temperature.
The trimethylamine removal rate was calculated using the following formula, and the results are shown in Table 5.
Trimethylamine removal rate (%) = {(initial trimethyl concentration−post-reaction trimethyl concentration) / initial trimethylamine concentration} × 100

(Test Example 20)
Using the Ti plate obtained in Example 19, plasma with a discharge power of 0.1 W was generated and a trimethylamine removal test was performed.

(Test Example 21)
A trimethylamine removal test was performed in the same manner as in Test Example 20, except that the Ti plate obtained in Comparative Example 8 was used.

As shown in Table 2, the CO removal rates in Test Examples 1 to 4 were 92% or more. Further, as shown in Table 3, the CO removal rate of Test Examples 15 to 17 was 92% or more. On the other hand, in Test Examples 5 to 7, the CO removal rate was 4% or less. From these results, it was confirmed that the gas treatment apparatus 300 using Examples 14 to 20 had superior catalytic activity as compared with the gas treatment apparatus 300 using Comparative Examples 6 to 8.

As shown in Table 2, in Test Examples 8 to 11, the CO removal rate after 1 hour was 92% or more, and the CO removal rate after 24 hours was 90.1% or more. On the other hand, in Examples 12 to 14, the CO removal rate after 1 hour was 4% or less, and the CO removal rate after 24 hours was 0%. From these results, the gas processing apparatus 300 using Examples 17 to 20 has excellent catalytic activity compared to the gas processing apparatus 300 using Comparative Examples 6 to 8, and can maintain the catalytic activity. I understand.

As shown in Table 4, in Test Example 18, the ammonia removal rate after 1 hour was 91.2%, and the CO removal rate after 24 hours was 90.8%. On the other hand, the ammonia removal rate after 1 hour of Test Example 19 was 1.8% or less, and the ammonia removal rate after 24 hours was 1.7%. From these results, it can be understood that the gas processing apparatus 300 using Example 19 has superior catalytic activity as compared to the gas processing apparatus 300 using Comparative Example 8, and can maintain the catalytic activity.

As shown in Table 5, in Test Example 20, the trimethylamine removal rate after 1 hour was 94.2%, and the trimethylamine removal rate after 24 hours was 93.8%. On the other hand, the trimethylamine removal rate after 1 hour of Test Example 21 was 2.2%, and the trimethylamine removal rate after 24 hours was also 2.2%. From these results, it can be understood that the gas processing apparatus 300 using Example 19 has superior catalytic activity as compared to the gas processing apparatus 300 using Comparative Example 8, and can maintain the catalytic activity.
From the above results, the effectiveness of the present invention was shown.

Claims

A support having a plurality of mesopores;
Oxidation catalyst particles comprising at least one of a noble metal, an oxide thereof, and an alloy of the noble metal and a transition metal supported in mesopores of the support,
A mesoporous catalyst body, wherein one mesopore communicates with at least one other mesopore in the support.
A support having mesopores obtained by drying and calcining a solution containing an alkoxysilane or metal alkoxide hydrolyzate and a polyoxyethylene alkyl ether, a polyalkylene oxide triblock copolymer or a cationic surfactant; Contacting a solution or colloidal solution of a compound corresponding to at least one of a noble metal, an oxide thereof, and an alloy of the noble metal and a transition metal, firing and / or reduction treatment is performed in the mesopores of the support. A mesoporous catalyst body obtained by forming oxidation catalyst particles containing at least one of a noble metal, an oxide thereof, and an alloy of the noble metal and a transition metal.
Mesoporous catalyst body according to claim 1 or 2 wherein the support is formed by a metal oxide or SiO 2.
4. The catalyst body according to claim 3, wherein the metal oxide is a compound selected from the group consisting of TiO 2 , Fe 2 O 3 , ZrO 2 , and CeO 2 .
The mesoporous catalyst body according to any one of claims 1 to 4, wherein the noble metal is one or more selected from the group consisting of gold, platinum and palladium.
The mesoporous catalyst body according to any one of claims 1 to 5, wherein the support is a powder.
The mesoporous catalyst body according to any one of claims 1 to 6, wherein an average pore diameter of the mesopores measured by a BET method is 2 nm or more and 10 nm or less.
The mesoporous catalyst body according to any one of claims 1 to 7, wherein an average particle diameter of the oxidation catalyst particles is 1 nm or more and 10 nm or less.
The mesoporous catalyst body according to any one of claims 1 to 8, wherein the supported amount of the oxidation catalyst particles is 0.1 to 30% by mass with respect to the support including the oxidation catalyst particles.
The mesoporous catalyst body according to any one of claims 1 to 9, wherein the mesoporous catalyst body is a gas oxidation reaction catalyst.
At least a first electrode, a second electrode, and a dielectric disposed between the first electrode and the second electrode, the gap between the first electrode and the second electrode A plasma generator that generates plasma by applying a voltage to generate discharge;
A flow path formed in a region where the plasma generated by the plasma generation unit is present and in which a gas to be processed flows;
A gas processing apparatus comprising: the mesoporous catalyst body according to any one of claims 1 to 10 disposed in the flow path.
A support having mesopores obtained by drying and baking a hydrolyzate of alkoxysilane or metal alkoxide, and a solution containing polyoxyethylene alkyl ether, polyalkylene oxide triblock copolymer or cationic surfactant; and noble metal The oxide, and a solution or a colloidal solution of a compound corresponding to at least one of the alloy of the noble metal and the transition metal, and performing firing and / or reduction treatment in the mesopores of the support. And a method for producing a mesoporous catalyst body, comprising forming oxidation catalyst particles containing the oxide and at least one of an alloy of the noble metal and the transition metal.